[Odachi]

I posted a thread about what a taper crimp was. And many people told me they don't crimp for their ARs. However, my reloading manual says you should always crimp .223 and 5.56 rounds. So my question is, is crimping absolutely necessary for an AR-15? Is it necessary for semi automatic handguns? How well does a taper crimp retain a bullet at the same depth in the case compared to a roll crimp?

 

[ThomasM4]

Depends I typically use a very light crimp on mine. What you need to watch out for is you case neck tension after you size your brass bullet diam is 224 and your case neck should be .221 gives you about .003 interferece fit .
This is the gauge I use https://ballistictools.com/store/case-mouth-gage-224-308

 

[fredj338]

Crimping requires a bullet with cannelure to be done right. Few if any match grade bullets have a cannelure. So in a word, no you do not need to crimp for the AR. Is it helpful, sometims, especially if you have old brass that has lost its neck tension, but in general, no, not needed.

 

[rangerhgm]

I can't address the AR15, but for a semi-auto hand gun you need to taper crimp to remove the bell from the case after seating the bullet. If you don't remove the bell the round will not fit into a case gauge.

 

[Odachi]

Thanks for the help. Hopefully I can get more information. Thanks again.

 

[FGWinFLA]

For what its worth to ya...
When it looked like the "Wicked Witch of the East" might be our next president, I went out & bought 4 AR 15s.

Then I realized I had to make ammo for them.

Since that time, I've made approx. 12,000 rounds of .223 / 5.56x45 ammo and shot about 1/3 of that.

Not a single round was crimped and I had no troubles with the ammo.
All ammo was 55gr FMJ, various brands of brass and the powders of choice are IMR 4895 and IMR 4064.

Good luck and happy reloading.

 

[unclebob]

A taper crimp is not a crimp at all but just removing the bell on pistol cartridges. You do not put a bell on rifle cartridges. The neck tension from sizing is what hold the bullet not the so called crimp. Yes you can crimp rifle rounds but then are you also sizing the bullet down. Pistol rounds headspace on the mouth of the case. But mostly held by the extractor.But does if the round should miss the extractor and round slides forward in the chamber.
For the most part bullets are made with lead. Lead you can smash and it does not spring back. Brass on the other hand does spring back. So if you crimp the round the bullet becomes smaller and the brass when it leaves the die springs back some. Now you have a loser bullet in the case.So all you are doing is removing the bell that you but on the pistol case.
Revolver rounds on the other hand. Unlike the pistol round where the bullet wants to move back into the case and have setback. Revolver rounds what to move forward and lock up the cylinder. On Revolvers you do put a roll crimp or pressing the mouth of the case into the cannelure groove on the bullet expecily with high caliber heavy recoiling rounds.This prevents the round from moving forward.But then with light recoil revolvers you can get by with out using a roll crimp. Like with some cowboy shooters with there real light loads don’t even remove the bell on the case. Or just enought that they will fit in the cylinders
Also like what Fred said for rifle bullets that have a cannelure you can use a roll crimp. Not all rifle bullets do. But then you can also if you want load the bullet longer or shorter than where the cannelure is on the bullet. Then you would not use a crimp.

 

[fredj338]

I can't address the AR15, but for a semi-auto hand gun you need to taper crimp to remove the bell from the case after seating the bullet. If you don't remove the bell the round will not fit into a case gauge.

You do not bell a rifle case mouth to seat, so no taper crimp is needed.

 

[rangerhgm]

rangerhgm said: ↑
I can't address the AR15, but for a semi-auto hand gun you need to taper crimp to remove the bell from the case after seating the bullet. If you don't remove the bell the round will not fit into a case gauge.

You do not bell a rifle case mouth to seat, so no taper crimp is needed.

He asked "Is it necessary for semi automatic handguns?"

That's what I was addressing.....

 

[sciolist]

With the way I have my MBF die set, most of my 9mm ammo would probably run fine in a Glock barrel without crimping, but crimping certainly makes it much more reliable.

I crimp mixed range brass and .357/.358 bullets to a finished diameter of .376+.

If you're actually belling the cases, then you'll probably need to run them through the crimp die to even get them to chamber, let alone case. But "crimp" is really a misnomer. All you should be doing is removing the bell. 9mm head-spaces from the case mouth.

 

[dkf]

You do not bell a rifle case mouth to seat, so no taper crimp is needed.

I do. Whether it is an actual flare or slightly expanded at the mouth from an NOE expander plug. I find it has helped improve concentrically. I use the crimp to take out the flare. Does not matter as much on bullets with a boattail though.

Crimping required? No, not unless you do some kind of flare.

 

[fredj338]

I do. Whether it is an actual flare or slightly expanded at the mouth from an NOE expander plug. I find it has helped improve concentrically. I use the crimp to take out the flare. Does not matter as much on bullets with a boattail though.

Crimping required? No, not unless you do some kind of flare.

For jacketed bullets? All you need is a chamfer & seat. Way less work on the brass. Only rifle I expand the case mouth on is 45-70, because I load lead bullets.

 

[ithaca_deerslayer]

Depends I typically use a very light crimp on mine. What you need to watch out for is you case neck tension after you size your brass bullet diam is 224 and your case neck should be .221 gives you about .003 interferece fit .
This is the gauge I use https://ballistictools.com/store/case-mouth-gage-224-308

Interesting, can you describe more how that gauge is used? I read the link but am not clear on when you measure.

Is the measure taken just before seating the bullet? Or is the seating and crimping process done, but without the bullet ever actually put in that process? Or is the bullet pulled out, somehow, and then the measure taken?

Dunno

 

[ithaca_deerslayer]

A taper crimp is not a crimp at all but just removing the bell on pistol cartridges. You do not put a bell on rifle cartridges.

Why would a bell be put on a handgun cartridge, but not on a rifle cartridge?

Especially if both are lead bullets? Or if both are jacketed bullets?

 

[ithaca_deerslayer]

Pistol rounds headspace on the mouth of the case. But mostly held by the extractor.But does if the round should miss the extractor and round slides forward in the chamber.

Are you saying that for the most part, the semi-auto pistol rounds are headspacing on the extractor?

If so, why isn't the plunk test done with the extractor as part of it?

And if the rim slips past the extractor, then aren't we going to have a failure to extract? So, if headspacing on the extractor, then wouldn't we plan on always needing to measure/determine overall length based on how the extractor is holding the shell?

Before this thread, I would have assumed/guessed that the extractor has enough play, wiggle, or flex, that it is not really determining the headspacing, but that the case mouth was. Dunno. I guess one could test by trimming the shell really short and seeing what happens. Maybe that test has already been done

 

[ThomasM4]

Interesting, can you describe more how that gauge is used? I read the link but am not clear on when you measure.

Is the measure taken just before seating the bullet? Or is the seating and crimping process done, but without the bullet ever actually put in that process? Or is the bullet pulled out, somehow, and then the measure taken?

Dunno

I use it when 1st setting up my full length sizing die with fresh soft brass to verifie that my expander ball is sizing the neck for the right amount of neck tension .
You can also use it for neck bushing dies to find out the right bushing for the amount of neck tension you want.
If you have any doubts about the neck tension it's a good tool to have to get a quick accurate measurement.

 

[unclebob]

In rifles, don’t know about lead, never used lead in rifles, Other than my muzzleloaders. But you chamfer the mouth of the case and because the shape of the base of the bullet. Allows the bullet to be seated without having to bell the mouth of the case for the bullet to be seated.

For the plunk test you are making sure the round will fit the gun and your COL is too long and the base of the case is not protruding above the hood of the barrel. It can be below but not above.
Other than the first time I check a new gun to make sure my COL is not to long for that gun and that bullet, I never use the barrel as a case gauge. I use a case gauge. And I also don’t have any match grade guns that the rounds would pass the gauge gauge but not the barrel.
Measure a bunch of brass and you will find the brass can be all over the place. But they all still work in the gun. It's also why you can shoot not recommended 45 gap in a 45acp, .40 in a 10mm gun. But if the round is not held back by the extractor the round would be too far forward not allow the firing pin to hit the primer. But as long as the gun fires the brass would be ejected.

 

[dkf]

Why would a bell be put on a handgun cartridge, but not on a rifle cartridge?

Especially if both are lead bullets? Or if both are jacketed bullets?

I use a lot of jacketed bullets in rifles with flat bases just like jacketed bullets in pistols. Like I said I am seeing less runnout with these bullets in rifle with just a little bit of flare. With boat tail rifle bullets it doesn't seem to matter near as much. All the cases get deburred at the mouth regardless, I like to do it most pistol brass too. For lead I use more flare than jacketed in either pistol or rifle.

 

[fredj338]

Why would a bell be put on a handgun cartridge, but not on a rifle cartridge?

Especially if both are lead bullets? Or if both are jacketed bullets?

If you use a lead bullet or coated lead bullet or even plated, the case mouth needs flaring to keep from scraping the bullet base, rifle or handgun. I know some that seat jacketed in handgun w/o flaring but then you get the occasional torn case mouth &/or scraped base. I chamfer rifle case mouths, never handgun. So belling for handgun is a must for me, regardless of bullet type.

 

[OXMYX]

I use a Lee trimmer, neck sizer and crimp die for 223. Works for me.